Improvement in molds for sewer-building



J. BURNS. Mold for SeWerBuilding. i

u y, 'Pj'xtenterd Dec. 23,1879.

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NJEERS. PHOTO-LITHOGRAPHER. WASHINGTON. D CV UNITED STATES PATENT CET-10E JAMES BURNS, OF `SAN ANTONI, TEXAS.

IMPROVEMENT IN M OLDS FOR SEWER-BUILDING.,

Specification forming part of Letters Patent No. 222,863, dated December 23, 1879 application filed August 1, 1879. i

To all whom it may concern:

Be it known that I, JAMES BURNS, of San Antonio, in the county of Bexar and State of Texas, have invented a new and Improved Mold for Sewenuilding, of which the following is a specification.

My improvements relate to molds or centerings for use in building sewers of concrete, artificial stone, or brick; and the `invention consists in a collapsible mold, made of con venient length, and ofthe cross-sectional shape required for the sewer, and fitted on wheels,

, fifteen feetand `of oval or other form in crosssection.

The frame consists of a top cross-rib, a, at

` each end, to which ribs are pivoted vertical side ribs, b b, that have their lower ends connected by toggle-bars c, which retain and brace the ribs b when the mold is expanded.

The ribs a b are covered by a sheathing, d, of wooden slats or sheet metal, except at the bottom, which is left open.

Extending lengthwise through the mold, and sustained by ribs a, is a shaft, d', from which chains or ropes t' extend to the jointed bars c. i,

The ends of shaft d project beyond the mold, and are formed with crank-handles., by which the shaft can be turned to wind the chain', and thereby draw the sides of the mold inward.

lThe mold is supported on wheels e, that are tted in suitable supports at the lower ends of the side ribs. These wheels facilitate the labor of shifting the mold as the work progresses. v

In building sewers with this mold, the bottom or base, of stone or concrete, is first laid in the trench at the required grade, and when this is set the mold is placed thereon and the sides and crown of the sewer formed around it to the length of the mold. A head, f, is attached tothe end of the mold by screws or other fastenings, and projects as a ange; or, when a sewer is commenced, a head will be used at each end of the mold, and the material laid up between them to form the first section of a uniform thickness. When the section is completed the head or heads f will be removed and the shaft d turned to draw the sides of the mold inward. This action allows the mold to drop down, so that the sides and crown are relieved, and the mold may be then drawn out to the position required for the next section, and expanded by relieving the chain.

There are springs g attached to bars c and ribs b, which tend to draw bars c downward and expand the mold. There are also braces h, hung on ribs a, which, when the mold is collapsed, catch on pins in side ribs, b, so as to give rigidity to the mold while it is bein g withdrawn. A

To prevent the sides of the mold from being forced inward when the sides of the sewer arerammed, the joint of the bars c may be litted to drop slightly below the center-line when the sides are expanded, and the springs g aid in accomplishing the same object.

By the use of the mold described the sewer may be built rapidly to any grade, with top and sides of uniform thickness, without joints, and with a smooth interior surface.

The trench may be lled as the workprogresses up to the crown of the sewer,-and the side walls thus strengthened while the material is setting.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent- 4 1. The collapsible mold or centering A,

mounted on wheels or rollers, substantially as nation, with the jointed bars or braces o, of

and for the purposes set forth. springs g, substantially as and for tbe purposes 2. A collapsible mold or centering for sewerdescribed.

building, consisting of oross-ribs ce, jointed side ribs b, sheathing d, toggle-bars c, headf, JAMES BURNS' shaft d', and chain or rope i', combined for op- Witnesses: eration substantially as described. DAVE S. BURNS,

3. In a collapsible sewer-mold, the eombi- ALBERT F. BEGKMANN. 

